Passcodes may be used in many situations where a user needs to be authenticated. Situations requiring authentication may include the ability to access or use a computer, mobile phone, PDA, or any other device. They may also enable access to a physical location, or allow use of a credit/debit card or similar instrument. Passcodes are typically alpha-numeric strings or sequences entered on a keyboard.
Eye-tracking technology can be used to select objects on a screen. The eye-tracking system tracks the gaze of a user and determines which object the user is looking at.
Like reference numerals are used in the drawings to denote like elements and features.